Researchers have designed a bioengineered jellyfish that can swim, an early step in scientists’ quest for a way to make fresh tissue for patients with damaged hearts.

Researchers have designed a bioengineered jellyfish that can swim, an early step toward potentially finding a way to make fresh tissue for patients with damaged hearts reports WSJ’s Gautam Naik.

.The lab-made jellyfish is created with a mix of silicone and rat-heart cells. Although it isn’t a living organism, the robot’s muscular structure closely resembles that of a real jellyfish, enabling it to swim freely through water.

Scientists hope that such techniques will make it possible to harvest cells from one organism and then reorganize them in sophisticated ways to make a bioengineered system for human use, such as a heart pacemaker that wouldn’t require battery power.

“What we’re trying to do is become really good at building tissue” for medical use, said Kevin Kit Parker, a bioengineer at Harvard University and a co-author of the study. “This is just practice” in the quest to reverse-engineer entire organs, he added.

Tissue-engineering experiments often rely on trial and error. Dr. Parker said he wants to bring to the field the same quantitative rigor and precision that civil engineers use in building bridges.

Dr. Parker spent years searching for a good model for the human heart. While watching a jellyfish at Boston’s New England Aquarium, he was struck by how the creature used a muscle to pump its way through water, a mechanism similar to a beating heart.

His Harvard team linked up with researchers at the California Institute of Technology, and the two groups first embarked on a detailed study of jellyfish propulsion: the complex arrangement of muscles; the contracting and recoiling motion of the bodies; and the fluid dynamics resulting from their swimming motion.

The engineers used a silicone polymer to build a centimeter-long jellyfish consisting of a membrane with eight armlike appendages. They overlaid muscle cells, obtained from a rat heart, on this membrane in a particular pattern. “We coaxed them to self-organize so that they matched the [muscle] architecture of a jellyfish precisely,” Dr. Parker said.

The robot, named “Medusoid,” was placed in salty fluid that can conduct electrical currents. When the engineers oscillated the voltage in the fluid, the muscle-coated membrane began to contract in a synchronized manner. (By contrast, a real jellyfish obtains nutrients by feeding on plankton, eggs, larvae, small fish and other jellyfish, which then enables specialized tissue to electrically activate the muscular contraction.)

The muscular contraction creates vortices—doughnut-shaped rings of water—below the creature’s body. For jellyfish, vortices propel it forward and push food toward its mouth.

The main difference between the two creatures “is that the real jellyfish can go and get nutrients and ours can’t,” said John Dabiri, a co-author of the study and a bioengineer at Caltech.

The engineers now plan to design a jellyfish that can gather food on its own. They also want to include specialized tissue, so that the creature can activate the muscular contractions internally, as a real jellyfish does.

The current version of Medusoid moves in a simple manner and can’t really turn or maneuver. To achieve that, the engineers will have to include multiple cell types and devise a system that allows the lab-built creature to sense its environment and use an internal “decision-making circuit” to pick different behaviors.

While those challenges are significant, some practical benefits may be more easily attained. Drug companies often test new heart drugs on cardiac tissue, and the jellyfish—which mimics a beating human heart—could serve as an alternative model. “I could put your drug in the jellyfish and tell you if it’s going to work,” said Dr. Parker.

The study of vortices already has inspired some new areas for medical research. For example, when blood enters the left ventricle of the pumping heart, it creates a rotating fluid mass that is similar to the vortices created by a swimming jellyfish. The vortices in the heart can be measured with ultrasound.

In 2006, Dr. Dabiri co-authored a study, involving 120 participants, which suggested that the process of vortex-ring formation could offer important clues about cardiac health. “You can tell healthy from less-healthy hearts” by studying the vortices, Dr. Dabiri said.